Due to the limited summer work period in Arctic regions, it frequently is desirable to lay offshore pipelines during the wintertime. This usually necessitates cutting ice slots so that the pipeline may be laid through the ice slot and down to the sea bottom. However, once the ice slot is cut, it quickly freezes back over, necessitating the use of some technique for keeping the ice slot free of newly formed ice during the time span in which the pipeline is being laid. Inasmuch as the Arctic regions present severe working conditions both to men and machinery, it is desirable that the ice removal apparatus be relatively simple, free of maintenance and resistant to breaking down. In addition, it is desirable that the apparatus be relatively light in weight since the ice may not support heavy structures, and that the forces that it transmits to the ice surrounding the slot as a result of removing the newly formed ice, be relatively low.
Applicant is not aware of any prior references which, in his judgment as one skilled in the pipeline art, would anticipate or render obvious the novel method and apparatus of the instant invention; however, for the purposes of fully developing the background of the invention and establishing the state of the requisite art, the following is set forth: U.S. Pat. Nos. 4,373,836; 4,205,928; 4,129,011; 4,126,013; 4,094,149; 4,053,406; 3,977,345 and 3,950,955.